https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117649
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jeff Law <l...@gcc.gnu.org>: https://gcc.gnu.org/g:065433b4ce8d9676ba3be4871c520b8257f21c14 commit r15-5482-g065433b4ce8d9676ba3be4871c520b8257f21c14 Author: Jeff Law <j...@ventanamicro.com> Date: Tue Nov 19 19:24:41 2024 -0700 [RISC-V][PR target/117649] Fix branch on masked values splitter Andreas reported GCC mis-compiled GAS for risc-v Thankfully he also reduced it to a nice little testcase. So the whole point of the pattern in question is to "reduce" the constants by right shifting away common unnecessary bits in RTL expressions like this: > [(set (pc) > (if_then_else (any_eq > (and:ANYI (match_operand:ANYI 1 "register_operand" "r") > (match_operand 2 "shifted_const_arith_operand" "i")) > (match_operand 3 "shifted_const_arith_operand" "i")) > (label_ref (match_operand 0 "" "")) > (pc))) When applicable, the reduced constants in operands 2/3 fit into a simm12 and thus do not need multi-instruction synthesis. Note that we have to also shift operand 1. That shift should have been an arithmetic shift, but was incorrectly coded as a logical shift. Fixed with the obvious change on the right shift opcode. Expecting to push to the trunk once the pre-commit tester renders its verdict. I've already tested in this my tester for rv32 and rv64. PR target/117649 gcc/ * config/riscv/riscv.md (branch on masked/shifted operands): Use arithmetic rather than logical shift for operand 1. gcc/testsuite * gcc.target/riscv/branch-1.c: Update expected output. * gcc.target/riscv/pr117649.c: New test.
